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2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Modernizing I&C for operations and maintenance, one phase at a time
The two reactors at Dominion Energy’s Surry plant are among the oldest in the U.S. nuclear fleet. Yet when the plant celebrated its 50th anniversary in 2023, staff could raise a toast to the future. Surry was one of the first plants to file a subsequent license renewal (SLR) application, and in May 2021, it became official: the plant was licensed to operate for a full 80 years, extending its reactors’ lifespans into 2052 and 2053.
Susumu Naito, Makoto Takemura, Shungo Sakurai, Mikio Izumi, Yasushi Goto, Yoshiji Karino
Nuclear Science and Engineering | Volume 166 | Number 2 | October 2010 | Pages 107-117
Technical Paper | doi.org/10.13182/NSE09-99
Articles are hosted by Taylor and Francis Online.
To simplify in-core instrumentation in a next-generation boiling water reactor (BWR), we study an ex-core nuclear instrumentation system. As a first step of this study, we focused on ex-core local power monitoring, which is especially difficult because neutrons inside a core cannot fly out of a reactor pressure vessel (RPV) due to shielding of fuel, water, etc., except when they are generated in the outer edges of the core. To resolve this, we created a local power monitoring method with neutron streaming pipes (NSPs). An NSP is a gas-filled pipe of size comparable to an instrumentation tube of an existing BWR. NSPs are axially inserted into the core. In-core neutrons are transported to the RPV through NSPs. The neutrons transmitted through the RPV are monitored with ex-core neutron sensors. We analytically evaluated the applicability of this NSP method for an advanced BWR (ABWR) with a three-dimensional BWR core simulator and the MCNP5 code. The ex-core neutron flux through the NSP was highly proportional to local power (1.0% of the residual standard deviation). The flux amount and the linearity gave feasible specifications for the ex-core neutron sensor in typical operation modes (pulse, Campbell, and current modes). Therefore, the NSP method is applicable to an ABWR.
